Clasps for straps or bracelets that use a buckle and tongue to join the two strands of the strap or bracelet to each other are known from the prior art. The strap or bracelet includes a first strand with said buckle and tongue and a second strand wherein holes are made. The second strand is intended for removable attachment to said first strand by engagement in the buckle. The buckle includes two lateral arms, each provided with a hole, a removable crosspiece whose ends are arranged to engage in the holes in the arms, and a tongue with an eye part rotatably engaged on said bar. The first strand has a transversely arranged end orifice close to a free end of the strand, for receiving said buckle bar, and an end notch that extends from said free end to beyond the end hole for receiving the eye part of the tongue. In fact, when the second strand is engaged in the buckle, the two strands are joined by the engagement of the tongue in one of the holes in the second strand. Thus, depending upon the hole in which the tongue is engaged, the second bracelet strand is engaged closer or further away in the buckle, tightening said bracelet to a greater or lesser degree.
However, one of the problems of this buckle of the prior art is that the second bracelet strand, which is engaged in the buckle, also passes through leather rings located on the bracelet strand to which the buckle is secured, so as to press the second strand onto the first strand. It is possible, when the bracelet is being worn, for stresses applied to the second strand to be such that said strand comes out of the leather rings, which may lead to the bracelet opening.